Answer:
![(31)/(70)\ lb](https://img.qammunity.org/2021/formulas/mathematics/high-school/5wszv9qkfdr8kk9wlagqncpinkvf5lh0g2.png)
Explanation:
Given:
They used 1/2 lb flour to make the bread.
They used 1/7 lb less flour to make bread than to make cookies
So they used flour to make the cookies =
![(1)/(2)+(1)/(7)](https://img.qammunity.org/2021/formulas/mathematics/high-school/f1vyxclk9szsibevniytp268sn4w85628t.png)
=
![(7+2)/(14)](https://img.qammunity.org/2021/formulas/mathematics/high-school/zbtky9dq27ytlaqbu0q1265a35bpi8xnwh.png)
=
![(9)/(14)\ lb](https://img.qammunity.org/2021/formulas/mathematics/high-school/ao1ov9z29gq6zn5hzgsoog7wkcuwxqzbgt.png)
Therefore they used
flour to make the cookies.
She used 1/5 lb more to make cookies than to make brownies.
So they used cookies to make the brownies =
![(9)/(14)-(1)/(5)](https://img.qammunity.org/2021/formulas/mathematics/high-school/yt2ow822ckqfuffnhcrfegnqo941m5srcj.png)
=
![(5* 9 - 14)/(70)](https://img.qammunity.org/2021/formulas/mathematics/high-school/zmseel1vgtlhujvnw7mot3xttuf2ocm3mb.png)
=
![(45 - 14)/(70)](https://img.qammunity.org/2021/formulas/mathematics/high-school/fv1r36bbx791uoge6lb8ez1fihdnwuilmp.png)
=
![(31)/(70)\ lb](https://img.qammunity.org/2021/formulas/mathematics/high-school/5wszv9qkfdr8kk9wlagqncpinkvf5lh0g2.png)
Therefore they used
flour to make the brownies.